Further refinements to history interfaces.

IPython/core/history.py

@@ -195,17 +195,26 b' class HistoryManager(Configurable):'
         return cur
         
     
-    def get_hist_tail(self, n=10, raw=True, output=False):
-        """Get the last n lines from the history database."""
+    def get_hist_tail(self, n=10, raw=True, output=False, include_latest=False):
+        """Get the last n lines from the history database.
+        
+        If include_latest is False (default), n+1 lines are fetched, and
+        the latest one is discarded. This is intended to be used where
+        the function is called by a user command, which it should not
+        return."""
         self.writeout_cache()
+        if not include_latest:
+            n += 1
         cur = self._get_hist_sql("ORDER BY session DESC, line DESC LIMIT ?",
                                 (n,), raw=raw, output=output)
+        if not include_latest:
+            return reversed(list(cur)[1:])
         return reversed(list(cur))
         
     def get_hist_search(self, pattern="*", raw=True, search_raw=True,
                                                         output=False):
-        """Search the database using unix glob-style matching (wildcards * and
-        ?, escape using \).
+        """Search the database using unix glob-style matching (wildcards
+        * and ?).
         
         Returns
         -------
@@ -620,19 +629,20 b" def magic_rerun(self, parameter_s=''):"
     """
     opts, args = self.parse_options(parameter_s, 'l:g:', mode='string')
     if "l" in opts:         # Last n lines
-        n = int(opts['l']) + 1
+        n = int(opts['l'])
         hist = self.history_manager.get_hist_tail(n, raw=False)
     elif "g" in opts:       # Search
         p = "*"+opts['g']+"*"
         hist = self.history_manager.get_hist_search(p, raw=False)
-        hist = list(hist)[-2:]
+        hist = list(hist)
+        if 'magic("rerun' in hist[-1][2]:
+            hist = hist[:-1]   # We can ignore the current line
+        hist = hist[-1:]       # Just get the last match
     elif args:              # Specify history ranges
         hist = self.history_manager.get_hist_from_rangestr(args)
     else:                   # Last line
-        hist = self.history_manager.get_hist_tail(2, raw=False)
+        hist = self.history_manager.get_hist_tail(1, raw=False)
     hist = [x[2] for x in hist]
-    if hist and parameter_s in hist[-1]:
-        hist = hist[:-1]
     if not hist:
         print("No lines in history match specification")
         return
@@ -647,7 +657,6 b' def init_ipython(ip):'
     ip.define_magic("rep", magic_rep) 
     ip.define_magic("recall", magic_rep)
     ip.define_magic("rerun", magic_rerun)
-    ip.define_magic("r", magic_rerun)
     ip.define_magic("hist",magic_history)    # Alternative name
     ip.define_magic("history",magic_history)
 

IPython/core/interactiveshell.py

@@ -1550,7 +1550,8 b' class InteractiveShell(Configurable, Magic):'
             readline.set_history_length(self.history_length)
             
             # Load the last 1000 lines from history
-            for _, _, cell in self.history_manager.get_hist_tail(1000):
+            for _, _, cell in self.history_manager.get_hist_tail(1000,
+                                                include_latest=True):
                 if cell.strip(): # Ignore blank lines
                     for line in cell.splitlines():
                         readline.add_history(line)

IPython/core/tests/test_history.py

@@ -59,13 +59,19 b' def test_history():'
             nt.assert_equal(list(gothist), zip([1,1,1],[1,2,3], hist))
             
             # Check get_hist_tail
-            gothist = ip.history_manager.get_hist_tail(4, output=True)
+            gothist = ip.history_manager.get_hist_tail(4, output=True,
+                                                    include_latest=True)
             expected = [(1, 3, (hist[-1], ["spam"])),
                         (2, 1, (newcmds[0], None)),
                         (2, 2, (newcmds[1], None)),
                         (2, 3, (newcmds[2], None)),]
             nt.assert_equal(list(gothist), expected)
             
+            gothist = ip.history_manager.get_hist_tail(2)
+            expected = [(2, 1, newcmds[0]),
+                        (2, 2, newcmds[1])]
+            nt.assert_equal(list(gothist), expected)
+            
             # Check get_hist_search
             gothist = ip.history_manager.get_hist_search("*test*")
             nt.assert_equal(list(gothist), [(1,2,hist[1])] )
@@ -92,3 +98,12 b' def test_extract_hist_ranges():'
                 (-7, 1, 6)]
     actual = list(extract_hist_ranges(instr))
     nt.assert_equal(actual, expected)
+    
+def test_magic_rerun():
+    """Simple test for %rerun (no args -> rerun last line)"""
+    ip = get_ipython()
+    ip.run_cell("a = 10")
+    ip.run_cell("a += 1")
+    nt.assert_equal(ip.user_ns["a"], 11)
+    ip.run_cell("%rerun")
+    nt.assert_equal(ip.user_ns["a"], 12)